Electrodeposition of In₂O₃ thin films from a dimethylsulfoxide based electrolytic solution

Indium (III) oxide (In₂O₃) thin films have been obtained after heat treatment of In(OH)₃ precursor layers grown by a potential cycling electrodeposition (PCED) method from a dimethylsulfoxide (DMSO) based electrolytic solution onto fluorine-doped tin oxide (FTO) coated glass substrates. X-ray diffraction (XRD) measurements indicate the formation of a polycrystalline In₂O₃ phase with a cubic structure. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed a smooth morphology of the In₂O₃ thin films after an optimized heat treatment had been developed. The surface composition and chemical state of the semiconductor films was established by X-ray photoelectron spectroscopy analysis. The nature of the semiconductor material, flat band potential and donor density were determined from Mott-Schottky plots. This study reveals that the In₂O₃ films exhibited n-type conductivity with an average donor density of 2.2 × 10¹⁷ cm^-3. The optical characteristics were determined through transmittance spectra. The direct and indirect band gap values obtained are according to the accepted values for the In₂O₃ films of 2.83 and 3.54 eV for the indirect and direct band gap values.